1. Field of the Invention
With reference to the classification of art as established in and by the United States Patent Office this invention is believed to be found in the field pertaining to "Surgery" and particularly to "flexible catheter guide".
2. Description of the Prior Art
Arterial blood infusion and withdrawal devices are known and the techniques of a guide wire inserted into the lumen of the artery is known and shown as prior art in FIGS. 1A through 1G to be hereinafter more fully discussed. A catheter placement system is shown in U.S. Pat. No. 3,416,531 to Edwards as issued Dec. 17, 1968; a guide for the catheter is also shown in U.S. Pat. No. 3,547,103 as issues to Cook on Dec. 15, 1970; a flash-back indicator is shown in U.S. Pat. No. 3,942,514 as issued to Ogle on Mar. 9, 1976; a withdrawal system using a guide wire is shown in U.S. Pat. No. 4,006,743 as issued to Kowarski on Feb. 8, 1977; a catheter placement assembly is shown in U.S. Pat. No. 4,046,144 to McFarlane as issued Sept. 6, 1977; an extraction device is shown in U.S. Pat. No. 4,215,702 as issued to Mayer on Aug. 5, 1980; a blood collecting device with indicator is shown in U.S. Pat. No. 4,154,229 as issued to Nugent on May 15, 1979; a needle and sheath is shown in U.S. Pat. No. 4,230,123 as issued to Hawkins, Jr. on Oct. 28, 1980, and a guide wire placement is shown in U.S. Pat. No. 4,274,408 as issued to Nimrod on Jan. 23, 1981.
Although the present apparatus may be used in both veins and arteries, penetration into the artery is the most difficult and requires the greater expertise. The preferred arterial catheter insertion site is the radial artery immediately proximal to the wrist. This site is preferred because the artery is relatively close to the skin and therefore relatively accessible. The position and orientation of the artery is normally located by detecting the pulse and following the pulse beat up the artery for about one inch or more in length. Some practitioners draw an ink line on the skin to show this position and orientation. The catheter and needle assembly is then introduced at an angle about thirty to forty-five degrees to the surface of the skin, with the bevel of the needle facing up, or toward the outer surface.
This method of insertion is a real challenge even to the most experienced practitioner. First, he must find the artery with the point of the introducer needle and obtain flashback through the hollow of the introducer needle. Many practitioners remove the existing flash plugs in hopes of being able to obtain a quicker flashback (indication of piercing the artery). These practitioners desire a quicker flashback in the hope that this will indicate entry into the artery before penetration through the back wall of said artery with the needle point.
The artery wall is both thick (to support arterial blood pressure) and elastic and as a result the needle significantly compresses or dimples the artery wall before penetration is achieved. When the needle finally penetrates the first wall the pressure in the artery causes the wall to pop back along the needle, leaving minimal resistance to further forward travel of the needle. The most common occurrence is for the point of the needle to bury itself in the back wall of the artery when the first wall of the artery "pops" back over the heel of the bevel and along the shank of the needle. To compensate for this, some practitioners actually twist the introducer needle about its axis after they have observed flash in the introducer hub. This maneuver is intended to orient the main bevel angle parallel to the back wall of the artery and lift the embedded point out of the back wall. Other practitioners tend to draw the introducer needle back after they see flashback on the assumption that the point is embedded into the back wall of the artery.
Once the practitioner has observed flashback in the introducer and has been able to slide the catheter forward a short distance on the introducer, he assumes that he is in the artery with the tip end of the catheter. At this point, however, it is not just a simple matter of sliding the entire assembly or the catheter alone up the artery as the axis of the introducer needle is disposed at a substantial angle to the axis of the artery. This needle, when and as positioned, cannot be advanced up an artery or vessel. Rather, the practitioner utilizes a delicate feel to slide the catheter off of the introducer needle and into and up the artery. This procedure requires the advancing catheter to bend at its point of entry into the artery. Many times the catheter becomes embedded in the wall of the artery and the practitioner must detect this problem by the feel of the catheter as the catheter is slid forward. If the practitioner does not follow this procedure a substantial risk of gouging the lining of the artery and inducing a severe thrombosis occurs.
In order to get the catheter into the artery the catheter is bent so as to follow the artery. At this point the practitioner usually retracts and readvances the introducer several times during each insertion and puncture of the artery. Each placement may entail half a dozen unsuccessful attempts. Each failed attempt further aggravates the problem, because the artery goes into "spasm". After a few unsuccessful attempts, the user gives up using the catheter unit in the started attempt and with a fresh new unit begins again. In a sampling of hospitals it was found that over two needle-catheter units were used to achieve each successful catheter placement as a further indication of how difficult it is to successfully place catheters in the artery.
Although a discussion of the drawings is made in the later part of this application it is my wish to clarify the fact that FIGS. 1A through 1G represent the taught procedure which Applicant's invention seeks to make obsolete. The taught procedure in this sheet of drawings is used to achieve catheter placement in blood vessels near the heart and throat areas and may and is often used with the femoral artery. Shown in this sheet of drawings is the taught steps for inserting and using a guide wire for placing a catheter. Numbers are employed for the purpose of identification.
In FIGS. 1A through 1G the present method taught for placing a catheter, particularly in the vessels of a human, is shown. This sheet of drawings is identified as "Prior Art" and is a procedure taught in medical schools and in hospitals.
In FIG. 1A a needle 20 is carried by a body member 22 so as to be manipulated and advanced into and thorough the skin 24 of the patient. An artery or a vein 25 is depicted and the entering tip of the needle penetrates the wall of the vessel sufficiently for a flashback indication. Particularly when an artery is penetrated, blood under pressure enters and flows through the hollow needle.
In FIG. 1B the needle 20 is shown at a rather acute angle to the disposition of the vessel and further penetration of the needle may cause penetration of the opposite or rear wall as above discussed. A guide wire 20 is advanced through the bore of the needle 20 and this wire is manipulated and advanced forwardly in small increments so that the wire 27 is advanced about one inch or more in the vessel 25 to lie in said vessel as shown. This guide wire is sufficiently flexible to be bent and be advanced adjacent the rear wall of the vessel.
In FIG. 1C the guide wire 27 is shown within the vessel 25 and the needle 20 is being withdrawn from the skin and the guide wire. Care is taken so that the guide wire is not withdrawn from the artery and skin and is left in the placed position.
In FIG. 1D the guide wire 27 is still in place but the penetrated opening by the needle is not sufficient for the entrance of a catheter into the skin so a knife 29 as carried by a handle 30 is brought to and adjacent the guide wire 27. The knife 29 is manipulated to enlarge the aperture in the skin and in this enlarged opening a catheter may be advanced along the guide wire.
In FIG. 1E a catheter 32 attached to a hub 34 is first threaded along the guide wire 27 then by rotation, as indicated by the arrows, is advanced into the enlarged opening in the skin.
In FIG. 1F the catheter 32 has been advanced along the guide wire with the entering end of the catheter now in the vessel and in a bent condition in which it is to be used. Not shown is securing means for preventing dislodgement of the catheter 32 from the skin opening and vessel placement. After the desired placement has been achieved the guide wire 27, having now achieved its purpose, is removed from the placed catheter. The arrow indicates such removal.
In FIG. 1G the placed catheter 32 is shown being connected at its hub end 34 to an infusion or tubular conduit 36. A tapered end 38 is used to connect this conduit 36 to the tapered socket conventionally provided in the hub 34 of the catheter.
It is to be noted that the use of a knife 29 and the enlargement of the entering opening into the skin of the patient is usually accompanied by the loss of blood. The sterility of the entrance into the skin and the catheter used therewith is often suspect. The improved embodiments to be hereinafter more fully described avoid or minimize the difficulties of the taught method of FIGS. 1A through 1G.
This procedure has a number of significant iimitations. It is a surgical procedure that is it must be performed in an operating room environment, personnel must be gowned, masked and gloved. During this procedure blood can and often does escape through the needle into the surrounding areas. This blood flow normally continues to flow around the guide wire after needle withdrawal and presents quite a challenge to the practitioner to further open the incision to allow a catheter to be placed (pushed) into the blood vessel. Unless the knife cut is just right a site for continued blood leakage is created. Many times after catheter placement the puncture area is sutured to stop leakage.